This application relates generally to the field of toilets. More specifically, this application relates to toilets including improved trapways configured to prevent a toilet, such as a wash-down toilet, from siphoning during its flush cycle.
Generally, toilets can be classified into two types based on the function of the flush cycle, with the first type being a siphonic toilet, and the second type being a wash-down toilet. In a siphonic toilet, an amount of water is quickly supplied during the flushing cycle to completely fill the trapway, which is typically S-shaped, with water. Air is removed from the trapway as it is filled with water, and a siphon is created, which rapidly evacuates any water and waste from the toilet bowl. The siphoning ends once the water level drops below the inlet of the passageway, thereby allowing air to be introduced. In a siphonic toilet, typically all of the water in the bowl is removed during the flush cycle, and therefore there is not enough water left in the bowl to act as a water barrier to block sewer gases (e.g., back flowing gases). Accordingly, after the siphon evacuates the bowl, water is added to the bowl to create a water barrier.
In a wash-down toilet, the trapway is generally not configured to induce a siphon. In a wash-down toilet, the water level in the toilet bowl is at equilibrium with the height of a weir or dam. When water is supplied to the toilet bowl during a flushing cycle, waste is carried out of the bowl by the excess water until the flush cycle is complete and equilibrium is reached. However, some wash-down toilets have a tendency for a siphon to occur during the flushing cycle. For example, if the water is introduced into the bowl too quickly, then a siphon can be induced in the trapway.
Furthermore, wash-down toilets generally are not configured to include a feature that refills the bowl after the flush cycle, since there is generally water left in the bowl following a flush cycle, unless siphoning has occurred. As a result, if siphoning occurs during the flush cycle of such a wash-down toilet, then more water may be pulled from the bowl of the toilet than may be desired.
Since adding a refill feature to wash-down toilets is relatively expensive and wastes water in the event there is no siphoning, there exists a need to prevent siphoning from occurring during the flush cycle in wash-down toilets without the addition of refill features.